This invention relates to solar collectors. More particularly, this invention relates to solar collectors made using fiber-reinforced concrete.
Steep increases in the cost of conventional forms of energy based largely on the increases in the cost of fuels to provide such conventional energy have focused attention upon the need for developing solar energy sources. The environmental effects of the use of fossil fuels to provide energy has provided further impetus toward the development of such solar energy alternatives. The efficient and economic collection of solar radiation should be the preferred means for heating and cooling of buildings, domestic hot water heating, and industrial process heat.
However, while much research has been conducted on the feasibility of the use of flat-plate solar collectors including the physics of high absorption and low emissivity surfaces, the successful commercialization of solar thermal energy largely depends upon developing a system that provides energy at a cost low enough to be competitive with energy from conventional fuels. This requires more than the development of highly selective surfaces capable of providing sufficient heat absorption over an average period of sunny and cloudy days. The economic viability of such a system requires that the solar collecting panels be relatively inexpensive, lightweight, and durable in construction. Among the characteristics of durability must be both strength and matching of thermal coefficients of expansion over the wide range of temperatures which are normally experienced in the collection of solar energy. The absence of such strength and thermal matching will otherwise result in a panel with a short life; a situation which will more than counter any positive effects from the use of low cost materials.
It is known to construct solar collectors using concrete materials. Alosi U.S. Pat. No. 4,164,933 describes a precast concrete solar panel with a pasageway within the concrete serving as a conduit for conveying a fluid to effect a heat transfer intermediate the proximate planar surface of the panel. While such a panel would provide durability, it would not be lightweight. Furthermore, heat transfer through the concrete from the passageway to the surface would be inefficient.